Belef Pneumatic Actuator Co., Ltd. - 瑞力流体控制无锡有限公司

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BG - Series Declutch Gearbox Operator

Gear Declutchable Handwheel for Safe Manual Operation

BG-series declutch gearbox operator were specially designed used for butterfly valve, ball valve and plug valve together with pneumatic actuators. -This device allows for manual operation during installation, system testing and in the event of a supply air-failure. -It can mount directly to many of the most popular rack and pinion actuators on declutch override.

Product Documents

BG gear operator.pdf

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Product Features

Ductile‑iron housing, worm‑gear pair, jaw clutch assembly, shift lever, limit locking device, operating handwheel, upper & lower connecting flanges, output square shaft, long‑life lubricating grease. The connecting flanges strictly comply with ISO5211 international standard, enabling direct connection to all kinds of rotary pneumatic actuators.

Working Principle：It adopts internal jaw clutch structure plus worm‑gear reduction transmission. Clutch engagement and disengagement is realized by the shift lever.

1. Automatic Pneumatic Mode (Normal Operation) The clutch stays disengaged, so the manual worm‑gear unit is decoupled from the output shaft. Compressed air drives the pneumatic actuator to operate freely while the handwheel remains idle and stationary. An interlock structure prevents the handwheel from spinning during pneumatic operation to eliminate potential safety risks.

2. Manual Emergency Mode (Air‑loss / Maintenance) Lift the limit pin and toggle the shift lever to engage the clutch. Then turn the valve shaft via the handwheel and worm‑gear drive. Thanks to the self‑locking feature of worm‑gear, the valve position stays fixed once you release the handwheel. You must switch back to the disengaged position before restoring pneumatic operation.

Product Features

1. Mechanical Interlock – Dual Protection When the clutch is disengaged, pneumatic operation does not drive the handwheel, effectively preventing operator injury from unintended rotation while protecting the worm gear assembly from pneumatic shock loads – significantly extending service life. 2. Effortless Worm Gear Reduction with Self-Locking High reduction ratio design substantially reduces manual operating torque. Once positioned, the handwheel automatically locks in place, preventing unintended movement caused by media differential pressure and maintaining stable valve position. 3. Simple & Intuitive Shift Operation External shift lever with positioning detents provides clear, positive engagement feedback. Distinct position indicators allow field personnel to quickly identify manual/automatic status at a glance. Select models also feature integrated valve position indication.

4. Standardized Universal Mounting ISO 5211 standard flanges ensure direct compatibility with all series of RA/RB rack-and-pinion and RC scotch-yoke pneumatic actuators. The output square drive supports 90° orientation adjustment to accommodate various on-site pipeline layouts.

5. Reliable Sealing – Built for Industrial Environments Precision-sealed housing factory-filled with long-life industrial lubricating grease. IP65 ingress protection rating ensures dust-tight and water-resistant performance, suitable for both indoor plant installation and outdoor exposed piping. Anti-corrosion coating provides reliable protection against humid and mildly corrosive environments.

6. Eliminates Bypass Piping – Reduces Project Costs For small to medium-bore pipelines, the manual override with clutch mechanism eliminates the need for expensive bypass valve loops. In case of air failure, direct manual operation is readily available – optimizing pipeline design and significantly reducing engineering investment.

Product Specifications

Model	Actuator Configuration		ISO 5211 Standard Flange				Handwheel Diameter (mm)	Gear Ratio	Torque (N·m)
	Actuator Configuration		Actuator Connection Dimensions		Valve Connection Dimensions
	Double-Acting	Spring-Return	Center Distance	Shaft Bore	Valve Connection Size	Shaft Bore
BG-138	DA50-85	SR50-75	F05/F07	14x14	F05/F07	14x14	180	38:1	180
BG-237	DA92-105	SR83-92	F07/F10	17x17	F07/F10	17x17	200	37:1	320
BG-335	DA125-140	SR105-125	F10/F12	22x22	F07/F10/F12	22x22	280	35:1	680
BG-450	DA160-190	SR140-160	F10/F12/F14	27x27	F10/F12 or F14	27x27	300	50:1	1200
BG-554	DA210-240	SR190-210	F14/F16	36x36	F10/F14 or F12/F16	36x36	400	54:1	2100
BG-658	DA270-300	SR240-270	F16	46x46	F16	46x46	500	58:1	3000
BG-766	DA350	SR300	F16	46x46	F16	46x46	600	66:1	3800
BG-8320	DA400	SR350-400	F25	55x55	F25	55x55	500	320:1	6600